Internal-combustion engine



April 24, 1945.

A. ROSSMAN INTERNAL-COMBUSTION ENGINE Filed Aug. 17, 1942 Sheets-Sheet l MS Q kumtu April 24, 1945.

A. M. ROSSMAN INTERNAL- COMBUSTION ENGINE 5 Sheets-Sheet 2 Filed Aug. 17, 1942 C 1 Q m J N% R 6. R Mb April 24, 1945. A. M. ROS SMAN 2,374,460

INTERNAL'GOMBUSTION ENGINE Filed Aug. 17, 1942 5 Sheets-Sheet 3 I 4&

P 1945- A. M. ROSSMAN I INTERNAL-COMBUSTION ENGINE Filed Aug. '17; 1942 5 SheetgkSheet 4 INVENTOR.

April 24, 1 45 A. M. ROSSMAN INTERNAL-COMBUSTION ENGINE 5 SheetshS heet 5 Filed Aug. 17, 1942 7 INVENTOR. Q [ZekzJZ/Za man Patented Apr. 24, 1945 ICE 2,374,460 INTERNAL-COMBUSTION ENGINE Allen M. Rossman, Wilmette, Ill. Application August 17, 1942 Serial Ne. 455,150

11 Claims.

This invention relates to-power translating devices, and more particularly to such devices as,

for instance, an engine, a compressor, or the like. I 4 4 A preferred embodiment of the present invention, as illustrated in the accompanying drawings, comprises a two stroke cycle internal combustion engine, which operates on the Junkers principle, that is, two pistons operate in opposition in the same cylinder. 4

7 It is one of the objects of the present invention to provide an improved means for transmitting power between a crank shaft and a reciprocating piston whether the direction of transmission of power is from the piston to the crank shaft, as in an engine, or from the crank shaft to the piston, as in a compressor. In accordance with one of the principles of the present invention there is provided a straight line motion mechanism for guiding one end of the piston rod in substantially a straight line. This mechanism connects the piston rod to the crank shaft connecting rod. 1 The straight line motion mechanism includes awalking beam pivoted on two floating supports, the parts being so proportioned that one point of the beam moves in substantially a straight line and another point thereof moves in a direction opposite to the direction of movement of the straight line motion point. One of those points of the beam is connected to the piston rod and the other pointis connected to the crank shaft connecting rod.

It is a still further object of the present invention to provide an improved arrangement of the cylinders andcrank casein power translating means of the above character. In the preferred exemplification of this feature of the present invention two cylinders are mounted with their longitudinal axes parallel to and spaced from one another, with the crankcase located centrally between the longitudinal axesof the cylinders and water chamber and two end gas chambers, the water chamber being incommunicable with the gas chambers. The means for dividing this space into a plurality of chambers consists of 4 a pair of end closures each of which comprises a pair of clamping rings having twoconcentric wedgeshaped gaskets between them so that upon clampingthe pair of rings together the outer gasket is pressed radially outwardly into intimate contactwith the interior of the jacket wall and the inner gasket is pressed into intimate contact with the outer periphery of the cylinder wall.

This provides a water-tight, gas-tight seal while I at the same time permitting relative movement of the cylinder wall with respect'to the jacket wall, which movement takes place when the cylinder expands by heating.

4 It is a still further object of the present invention to provide an improved means for mounting an engine cylinderin place. In accordance with the preferred embodiment of the present invention the engine cylinder is mounted upon two end plates which embrace the jacket.- The jacket is anchored to one of the end plates and is slidably supported by the other end plate by a sliding joint which makes a sealing fit with the jacket. By this arrangement the jacket is free to expand between the supports. The ends of the cylinder within the jacket are free to expand with respect to the jacket and with respect to the'supports.

- Asa result of this arrangement any expansion of with the axis of rotation of the crank at right angles to the plane determined by the longitudinal axes of the cylinders. The crank shaft preferably has two crank throws 180 apart, each crank throw beingconnected to diagonally oppositepistons of the respective cylinders. This arrangement produces anced structure.

It is a further object of the presentinvention to produce a new and improved cylinder design for a water cooled internal combustion engine. The cylinder is provided with a jacket cast as an integral partthereof. The space between the cylinder and the jacket is divided into a central a sturdy, compact, and balthe cylinder or of the jacket can take placefreely without unduly stressing the parts.

In an internal combustionengine of the type here involved it is desirable to pre compress a volume of air which can be used for scavenging the burnt gases from the cylinder and for providing a fresh charge of air for combustion of the fuel upon the next power stroke. The back face of the cylinder moves in a chamber which constitutes a compression chamber for compressing the air. As a result it is necessary to provide a gland box for the piston at the point where the piston leaves this auxiliary gas compressor. The gland box includes gaskets for effecting a sealing fit around the piston as the piston slides within the gaskets. It is thus necessary that the center line of the gaskets be exactly coincident with the center line of the piston. The gland box is supported ports the gland boxthere is provided a flexible bellows-like structure, one end of which is sealed to the plate and the other end of which is sealed to and supports the gland box from the plate. As a result of this arrangement there is provided a floating support for the gland box which permits positioning of the gland box accurately with respect to the center line of the piston ring. There is thus eliminated the need for extreme accuracy in locating the bolt holes for bolting the gland box support to the rest of thestructure.

Oil cooling of the pistons in an internal combustion engine has been proved to be an effective means for reducing wear on pistons, rings and cylinder walls, of preventing gumming and carbonizing of lubricating oil in the piston rod grooves, of increasing the load capacity of the engine and of reducing the tendenc .to develop cracked piston heads. It is one of the objects of the present invention to provide an improved means for oil cooling the pistons. result the piston rod is hollow to constitute a passageway for cooling oil to the head of the piston. A gland box which is filled with oil and maintained under, pressure supplies cooling oil to the piston rod. The gland box is suitablyfgasketed around the piston rod to prevent creepage of any cooling oil along the piston rod into the air pressure chamber on theback side of the piston. Suitableventing means in the gasket-constitutea. drainage system to take :care of any oil that may creep past the gasketat the inner end of the gland box. A tube inthe hollow piston rod serves as a return duct to-carry the 01-]. back from the piston. The pistons are thus liquid cooled without the introduction of the usualswinging jointed pipe connections betweenthepiston and the source of supply or" the cooling liquid. V

It is a still further object of the present inventionto provide an improved means for adding auxiliary gas compressor units to the engine forproviding additional compressed airor other gases. Such gases. may b'e needed for operation of the engine, as for greater scavenging or the like, or for supercharging the fuel, or as may be needed for purposes apart from the-opera tion of the engine as, for instance, for providing compressed air for auxiliary controlled-devices. Since the end ofthepistonrod remote from the piston is guided to move in a straight line, that point may also constitute 'a connection point to a piston rod of an auxiliary gas compressor which maybe mounted coaxially with-the power piston of the engine.

The attainment of the above and'further objects of the presentin vention will be apparent from the following specification taken in conjunction'with the accompanying drawings forming a part thereof.

In the drawings:

' Figure l is a side view, in partial section,'of a two stroke cycle ignition type gas engine embodying the present invention;

Figure 2'is a sectional view taken along the line 2+2'of Figurel' and'looking in the direction of the arrows;

Figure 3 is an enlarged longitudinal sectional view of the piston and piston rod assembly and the adjacent'parts of the cylinder;

Figure 4 is a'sectional view taken along th line 4 5d of Figure 1 and looking in the direction of the arrows; v

I Figure, 5 is a sectional view taken along the line 55 of Figure 1 and looking in the direction of the arrows; V

Figure 6 is a side elevational view, in partial To effect this section, of a somewhat modified form of engine for Diesel operation;

Figure '7 is a diagrammatic view of the engine of Figure l with the pistons in one extreme position and illustrating the method of ascertaining the design of a walking beam for converting the engine of Figure 1 to the Deisel type engine;

Figure 8 is a view similar to Figure 7 and showing the pistons in their opposite extreme positions;

Figure 9'is a front view of a walking beam used for converting the engine of Figure 1 from a gas engine to a Diesel engine;

Figure 10 is a front view, in partial section, of a combination engine and two stage air compressor; and

jacket 4 constitute one integral casting. The

cylinder 3 is provided with an opening 5 located substantially centrally of the cylinder, which opening 5 is adapted to receive the usual Diesel type injector nozzle, or a spark plug if the engine is to be used as a gasengine. The cylinder is additionally provided at one end With a group of exhaust ports 6 and at the other end with a group of inlet ports 1. The ports 6 and l extend around the entire periphery of. the cylinder 3. The ports 6 open into a jacketed exhaust outlet 9 that leads to the atmosphere. The ports. I open into a space I0 between the wall of the cylindert and the jacket 4.

This provides a water-tight, gas-tight seal for the water chamber between the closures l2 and i3 and between the wall of the cylinder 3and the-Wall of the jacket -4.- At the same time if the wall of thencylinder 3 expands axially an amount greater than theexpansion of the wall of the jacket 4, the. cylinder v3 can slide with respect to the closures I2 and t3.

The cylinder 3 is provided with an additional series of ports 20 and 21 at opposite ends thereof, both of which series'of ports extend around the periphery of the cylinder and open into-the space H] between the cylinder 3 and the jacket 4. The space between the cylinder 3 and the jacket- 4 is.

thus divided into a central water compartment which is incommunicable with the two end .air compartments Ill. The two end compartments communicate with one another through a duct-2 3 that also communicates through a check valve 24 to the atmosphere in the case of a Diesel engine, and in the case of a gas engine toa-fuel-air line that leads from the usual carbwreting device.

This permits the flow of an air-gas mixture from the usual carbureting device into the duct 23 when the pressure in the duct 23 is below that on theoutlet side of the valve 24, but which prevents the flow from the duct 23 through the check valve when the pressure in the duct 23 is above that in the fuel-air line. l

The two cylinders l and 2 are supported by a. pair of end plates 30 and 3|. To that efiect the jacket 4 of each cylinder has a peripherally extending'flange 32 adjacent to but spaced from one end of the jacket and. integral therewith. This flange is bolted to the end plate 3| by a series of bolts 33 and 34, as may be seen in Figures 1, 4 and 5. The bolts 33 extend from the left hand side of the flange 32 through the end plate 3| in which they thread. The bolts 34 extend from the right hand side of the plate 3| through the plate 3| and through the flange 32 and receive a nut n the left hand side of the shank of the bolt. The head of each bolt 34 rests in a pocket or recess 35 in th plate 3|, which pocket is of sufficient size to permit gripping of the head of the bolt by a suitable tool for turning of the bolt. The reasonfor the different arrangement of the bolts 33 and 34 will be apparent as this description proceeds. It is sufficient here to state that by the'arrangement thus far described the jacket 4 of the cylinder 2is rigidly secured to the end plate 3|.

The end plate 30 slidably supports one end of the jacket 4 of each cylinder or 2. eifect the end of the jacket extends into a circular hole through the plate 30. A ring 36 is located on the outside of the jacket and is slidable thereon. A gasket 3'! is positioned around theoutside of the jacket between the ring 36 and the end plate 36. The ring 36 corresponds to the flange 32 differing therefrom only in that the ring is not integral with the jacket, whereas the flange is. The ring 36 is secured to the end plate 36in much the same manner as the flange 32 is secured to the plate 3|, as by bolts 33' which correspond to the bolts 33, and bolts '34 which correspond to the bolts 34. The bolts 33 screw into the plate 36 whereas each bolt 34 has its head seated in a pocket in the plate 3|! and its shank extending through the plate and through the ring To this friction bearings 49 carried by the crank case 42.

The crank shaft 48 includes two crank throws 50 and 5|, 180 apart. The axi of rotation of. the shaft 48' is located centrally between the ends of each cylinder, midway between the two cylinders, with its axis at right angles to the plane determined by the longitudinal axes of the cylinders 3; The crank throw 56 has two crank connecting rods 6Z-53 secured thereto, and the crank throw 5| has two crank connecting rods 54 and connected thereto. The crank connecting rods 52 and 54 extend from the left hand side of the crank case as seen in Figure 2 and the rods 53 and 55 extend from the right hand side of the crank case.

Each cylinder 3 is provided with opposeddouble acting pistons Bil and 6| of identical construction. The piston and its associated piston rod and gland box construction is illustrated more fully in Figure 3. The piston 6|] is provided with a chamber 62 at the head thereof, which chamber is closed at the front by the front working face 63 of the piston, and is closed at the back by a rear wall 64 which is provided with a central opening into which a hollow piston rod 35 extends, the piston rod being provided with a parallel flange 66 for bolting to the wall 64 of the piston. The piston rod is secured at its opposite end to a fitting 68 which is mounted for oscillation in a straight line, as will be herein-- after described. A pipe 69 extends through the interior of the hollow pistonrod 65 and extends into the piston and is supported at its end bythe piston. The space between the pipe 69 and the 45 inside of the bore of the piston rod 65 constitutes 36 to receive a tightening nut 39(Fig. 3). The 50 gasket 31 is tightly pressed by the bolts to effect a liquid-tight, air-tight seal around the outer periphery of the jacket and between the jacket and the plate 30. A similar but much thinner gasket is provided between the flange 32 and the plate 3|, this last mentioned gasket being much thinner because there is no sliding movement between the plate 3| and the flange 32. By the arrangement thus described it is apparent that the right hand end of each cylinder jacket is rigidly secured to the end plate 3|, whereas the left hand end of each cylinder jacket is slidably supported by the end plate 39. The ends of the cylinders 3 extend through the end plates 30 and 3| but are freely slidable with respect thereto.

Thus both ends of each cylinder are free to expand lengthwise, and one end of the jacket is anchored, whereas the other endi free to expand lengthwise.

A crank case 42, which is rectangular in cross section, is bolted to the end plates between the two cylinders and 2, as may be seen from Figures l, 2 and 6. There is a small space 43 between the crank case and each cylinder, which space is of greater width djacent the ends of the a passageway for the forcing of cooling oil into the chamber 62 for cooling the piston. The oil returns from the chamber 62 by way of a passageway If! to the pipe 69, and through the pipe 69 to an outlet H in the fitting 68, from which it flows into an end chamber which will be more fully described a this description proceeds.

The piston rod 65 is supported by a gland box 74. The gland box includes an end plate 15 having a metallic bellows 16 sealed thereto at TI. The inner rim of the bellows is sealed at 78 to a metal tube 19 that has an end closure 86 through which the piston rod 65 slides. A sealing gasket 8| surrounds the inner end of the 0 piston rod 65 and bears against the end closure 80 and is pressed thereagainst by a sleeve 82 that has an inturned end 83. A sealing gasket 84 presses against the piston rod 65 at the end of the sleeve remote from the piston. Another end plate 86 surrounds the piston rod 65 and presses against the gasket 84. A pair of through bolts'8'l, which are apart, extend from the end plate 86 to the end plate 80 (Figs. 1 and! and serve to draw themtightly together, thus compressing the gaskets B|84 between the sleeve 82 and the end plates 86 and 86 respectively. The sleeve 82 is thus supported from the end plate 15 through the flexible bellows 16 so that if the plate 15 is a slight amount oil center with respect to the longitudinal axis of the cylcylinders than at the center thereof. Each end inder 3 the sleeve 82 is free to adjust its position so that its center coincides with the longitudinal axis of the cylinder '3.

A pipe 90 maintains a continuous .flow of oil under pressure to the interior of the'sleeve 82.

This oil flows from the sleeve to the interior.

of the piston rod 65 by way of a series of openings 9| (Fig. 3) in the piston rod,-and then flows into the piston, thence through the passageway I and pipe 69 to the outlet II, thus maintaining a continuous flow of cooling oil'to the head of the piston.

.It is desirable that there shallbe no creepage of oil from thesleeve 82, on the outside of the piston rod 65, past the sealing gaskets 8I. To prevent such creepage of oil the gasket 8| is provided with a plurality of by-passes 33 that extend from the piston rod 65 to the outside of the sleeve 82. Thus any oil under pressure within the sleeve 82 which may happen to creep past part of the gasket 8| will encounter the by-pass 93 .and flow outwardly therethrough without creeping along the rest of the piston rod past tively. Each housing has two similar straight line motion mechanisms I02 and I03 mounted therein. The straight line motion mechanism I02 is of a construction-such as is shown more particularly in my Patent No. 2,198,635, issued April 1940, to which reference may be had for a more complete description thereof. Briefly, the straight line motion mechanism includes two similar links Ni s-4H5 pivoted about fixed pivots I06-I 01 and supporting a pair of movable pivots I08I09. A rigid walking beam H0 is pivoted to the two movable pivots IE8 and I09. The fitting 6B is secured to the walking beam IIO by a pivot pin l I I the center of which is on the perpendicular bisector of a line joining the centers of' the pivots I03 and I09, as may be seen from Figure l. The distance between the centers of the fixed pivots IBIS-I 01, the lengths of the links Ili d-405, the distance between the movable pivots I08 and H19 and the distance of the pivot I I I from. the movable pivots are so proportioned that the locus of the point III is a straight line within the limits of travel of the piston rod. The proportions of the links required for pro ducing a straight line, motion of the point m may be obtained from my patent above referred to. The lower end of the walking beam H0 is pivotally connected to the crank connecting rod 55 by a pivot pin H2, as may be seen from Figures 1 and 4. The straight line motion mechanism I02 thus connects the piston rod of the upper right hand piston of Figure 1 with one connecting rod in such amanner that the end of the piston rod is guided by the straightline motion mechanism in a straight line and transmits its power through the walking beam I10 to the connecting rod 55, thence to the crank shaft. In a like manner the straight line motion rnechanism 03 connects the lower right hand piston rod with the crank connecting rod 53 by a pivot pin H3. 1

The housing IOI has a rectangular opening I i5, covered by a closure plate IIB bolted thereto,

By removing the plate IIE access is had to the interior of the housing IN. The end of the housing 'IOI also has'a. Wall I20 in which an opening II! is formed and in which there are also formed openings for each of the cylinders 3, as indicated at I2I in Figure 3. The end plates I5 of the gland box .14 are bolted to the plate I20 of :the housing II as by bolts I26. The wall I20 extends beyond the main body of the housing to form an outwardly extending peripheral flange I23 which is bolted 'to the end plate 3| by bolts I24, as may be seen from Figure 4. Thusthe housing I-0I is secured to the end plate An-explanation will now be given of the manner of assembling the engine. The closures I2. and I3 for forming the water chambers of the cylinder are individually assembled. Thereafter the :two cylinders are mounted on the end plates 30 and 3I in the manner previously described and then the crank case 42 is mounted between the end plates. At that time access to 'thebolts 46 is obtained by way of the opening 44 in the end plates 30 and 3I and the corresponding opening in the crank case. This constitutes one assembled unit.

The straight line operating mechanisms I02 and I03 are then assembled within the housing ml which, at that time, is preferably not yet bolted to the end plate. The piston and piston rod and the associated gland box "I4 are then assembled together. The plate I5 of the gland box is'then bolted to the plate I20 of the housing IOI. At that time access to the bolts I26 is had throughthe opening III of the housing IOI. The fitting 68 at the end of the piston rod assembly 65 is then secured to the corresponding straight line motion mechanism by inserting the pivot pin I I l through the walking beam I I0 and the fitting 66. The housing IIlI is then brought up towards the end plate 3i and the two pistons carried by the housing IOI are then fitted into the corresponding cylinders '3 into which they slide. At the time the housing IOI with the pistons extending therefrom is brought up against the plate 31 and before the pistons have been slid into the cylinders the pistons may be very slightly out of alignment with the cylinders. If this is the case they need merely be pushed up or down or sideways, as the case may be, to bring them into the cylinders, the flexilble metal bellows l3 permitting such movement of the gland box I4. Thereafter the pipe can be threaded into the gland box from outside the "housing I0 I. It is then a simple matter to connect the respective crankcase con necting rods 52, 53,54 and 55 to the respective walking beams of the straight line motion mechanisms. The provision of the removable plate I I6 permitsreaching into the housing I0! for making those connections. Thereafter the closure plate I I6'may be bolted in position to close the housing IOI.

It is to be noted that the flange I23 of the housing -IOI bears against one side of the end plate 3|, a suitable sealing gasket being interposed.

It is for thatreason that the bolts 34 of the plate 3|, rather than on the left hand side of that plate. Since theflange I23 and the wall I of the housing IDI must bear against the end plate 3|, that plate is provided with the recesses for the heads of the bolts 34 so that the heads of those bolts do not prevent the wall I 20 and its gasket from lying flat against the plate 3|.

Each of the two end housings lllll|0l for the straight line mechanisms is designed as a single piece. The two pistons that are associated with each end housing can be removed by disconnecting their associated connecting rods, then unbolting and removing the housing. When the housing is removed all of the parts of the straight line mechanism within it are accessible.

The four pistons of the two cylinders are so connected to the two crank throws that the movement of the pistons in one cylinder are displaced 180. from the movement of the corresponding pistons in the other cylinder. To permit two pistons in the same cylinder to be connected to adjacent throws on the same 'crank shaft the walking beams H0 and I [0' at theopposite ends of each cylinder are inclined laterally in opposite directions, as may be seen from Figure 4, but the axes of all bearings and pins that are associated with them are made parallel to the axis of the crank shaft.

An explanation will now be given of the mode of operation of theengine. Assume that the pistons 60 and BI are in the positionillustrated in Figure l. The cylinder 3 has been scavenged of the. burnt gases from the previous working stroke and is now filled with an air-gas mixture which entered the cylinder by way of the ports I. As the pistons approach one another they first close the intake ports I and then close the exhaust ports 6. Upon further movement of the pistons towards one another the air-gas mixture within the cylinder is compressed. As the pistons approach one another after the ports 1 are closed by the piston 6! the chamber at the back of the piston is being increased in size. Since thatchamber communicates with the chambers ill by way of theports 2fl--2| there is a resulting reduction of pressure in the chambers |0Hl, with the result that an air-gas mixture is drawn in from the carbureting device by way of the check valve 24. Thus as the pistons continue to move towards one another within the cylinder they continue to draw in the air-gas mixture from the carbureting device into the chambers It. When the pistons have approached one another the full extent of their travel ignition of the fuel 4 takes place, thus forcing the pistons apart. This is the power stroke of the cylinder. As the pistons Bi! and 5! recede from their innermost position towards theposition illustrated in Figure 1 they compress the. air-gas mixture on the back sides of the pistons. This results in the immediate .out of the cylinder through the ports 6 and fill the cylinder with a fresh air-gas mixture for the next cycle of operation.

During the power stroke of the pistons the piston rod moves the walking beam I to about its pivots, to the position illustrated in full lines in Figure 1, and it moves the corresponding walking beam Ill) to the position illustrated in dotted lines in Figure 1 and thus throughthe connecting rods 55 and 52 actuate the crank shaft.

The pistons are maintained cool by circulating oil underpressure through the pistons. The pipes 90 are connected to an oil pump which supplies oil under pressure to the pipes. The' oil flows through a pipe 90 into the gland box .14, thence through the openings 9! (Fig. 3) into the piston, then out again by wayof the passageway 10 in the piston and pipe 69 to the outletll, from which it flows into the end casing Hi0 or AM, where it is again picked up by theoil pump and recirculated. As there is no possibility of the cooling oil flowing into the cylinder in view of the drainage by-pass 93, the oil that is circulated in the pistons is not'contaminated andhence does not have to be replaced by fresh oil at frequent intervals.

It is to be noted that the pistons of the two cylinders are 180 apart so that while the pistons of one cylinder are making the power stroke the two pistons of the other cylinder are making the compression stroke. The impulse that is set up byan explosion within a cylinder acts equally and in opposite directions on both pistons and on the two cranks 180 apart, and reacts equally in opposite directions through the length of the crank case. Hence each dynamic force is balanced by a corresponding dynamic force of equal value acting in the opposite direction. With the cranks thus spaced 180 apart these forces form a balanced couple that has a minimum tendency to distort the crank shaft and little tendency to built up high pressures on the main bearof the present designe does notrequire a heavy closing of the check valve 24,.with the' result that the continued recession of the pistons from one another continues the compression of the air in the compression chamber rearward of the pistons and including the chambers Hi and duct 23. As

the pistons continue to recede under the pressure of the burnt gases in the cylinder 3, the piston an. ultimately commences to uncover the ports 6, before the piston 6! has commenced to uncover the ports 7. As a result of the uncovering of the ports 5 the burnt gases within the cylinder are discharged through the ports 6 and to the exhaust outlet 9. l A moment after the first uncovering of theports 6 the piston 6| uncovers the ports I. This causes the compressed air-gas mixture from foundation.

The bearings of the straight line mechanism can be either plain hearings or anti-friction bearings. In the event that play develops in the bearing'of the straight line mechanism there can be no pounding as a result because whereas in the four cycle engine the forces whichact on the bearings reverse, in the two cycle engine they act continuously in one direction. This characteristic permits both of the two connecting rods that are brought fromopposite directions to the same crank throw to have full width bear.- ing surfaces against the crank. This is accomplished by so designing the bearing surface on the end of each connecting rod that it will encircle slightly less than of the crank bearing surface, and then holding both ends in place either by a pair of floating clamp rings that encircle the outside half bearing shells of both rods or by two half rings each of which is bolted to the end of one rod and encircles the half bearing shell of the other.

Reference may now be had more particularly to the embodiment of the invention illustrated in Figure 6. Insofar as the structure of this engine is the same as that of the engine previously described, similar reference numerals have been used, The engine of Figure 6 diifers from that of Figure 1 mainly in that the end housing IIlI is provided with two additional cylinders I 35-I 36 of identical construction, to form additional air compressors. Each of the cylinders ass me is provided with a piston I37 and a connecting rod I38 that is connected to the fitting 58 that joins'the straight line motion mechanism with the power piston rod. The cylinder I35 connects with the duct 23 by way of a duct I39. When the piston rod moves to the left, as seen in Figure 6, the piston I31 is also drawn to the left to draw air from the atmosphere into the cylinder I35 by way of the duct I39 and the check valve 24. When the piston I3] reaches its extreme left hand position and then reverses its direction of travel, the1check valve 24 closes, and the piston I3l'compresses the air within the chamber I35 and adds it to the air-being compressed at theback of the pistons 60 and GI ofFigure 1. This provides an additional amount of compressed air for scaveng ingthe cylinder and for furnishing compressed air to the cylinder.

When the auxiliary cylinders I35 and I36 are usedifor increasing the scavenging ratio, as illustrated in Figure 6, they require no additional valves and are light in weight, hence do not increase the cost of theengine by any appreciable amount. Insofar as the cylinders I35-'-I36 in-' crease the scavenging ratio they permit an increase in the output of the engine.

Figure 6 illustrates one way of connecting a compressor to a piston rod of the engine of Figure- 1. In the embodiment illustrated in Figure 6 the compressor formed by the cylinder I35 suppliesits compressed air to the engine. lit may, however, be used to supply its compressed air to any other device or devices that may utilize compressed'air, since the device I35 is a comv pressoroperatedby the engine.

While I have shown the engine as mounted with the cylinders horizontal, it is apparent that end plates 303I can be supported in a horizontal position so that the cylinders are vertical, without affecting the mode of operation of the engine. It is further apparent that while the engine has been illustrated as operating on the Diesel principle, it may operate as an ignition type engine by providing means for admitting gas fuel immediately preceding or during the early stage of the compression stroke, and the usual spark plugs adjacent the inlet ports 5, as is well known in the gas engine-art.

It is sometimes necessary to provide a Diesel type engine which may thereafter be converted to a gas engine. This isparticularly so in oil drilling operations. A-Diesel type'engine is used for operating the drilling mechanism. Later the same engine is to be used to operate the oil pump. At that time gas is available and it is therefore desirable to operate the engine on the gas principle. The engine of Figures 1 tomay be converted fromthe gas engine to a Diesel engine or vice versa with a minimum change in parts.

Only the walking beam I lfl'between each-piston rod and its associated connecting-rod need be changed. Assume that'an engine such as shown in Figure 1 has been constructedto operate as an ignitiontype gas engine and it is desired to convert that engine to a Dieselengine. In a Diesel engine the clearance volume between the opposite pistons during the compression stroke is less than in an ignition type gas engine. It is thus necessary to increase the inward stroke of the pistons in order to decrease the clearance volume to that required for Diesel operation (a compression ratio of 16 to 1). In accordance with the principles of the present invention all of the increase in piston travel can be madezto take place on the inward end of the stroke so that at the outward end of the stroke the position ofthe piston with reference to the port openings '6'! in the cylinder wall will be unchanged. Thus the change over from gas to Diesel operation or vice versa can be made without changing the piston or the connecting rod. As previously stated, the only change that need be made is to replace the walking'b'eam II 0 by another walking beam.

An explanation. will now be given of the manner of' locating the pivots of the new walking beam, for which purpose reference may be had to Figures 7 and 8. In Figure 7 the pistons 60-6I are shown in the outermost position being connected to a walkin beam supported by the links IM- and I05 at the pivot points I08 and I09, the walking beam being pivoted to the piston rod at III. The point I40 represents the point of connection between the connecting rod '55 and the walking beam for gas engine opera tion. With the connecting rod 55 as a radius and the center of the crank 48 as a center an arc I4! is drawn on the walking beam. The piston BI is then moved inwardly to its innermost position for gas operation, which is the position illustrated. in full lines in Figure 8. The pivot pin which joins the connecting rod 55 with the walking beam at I40 is then removed. This permits shifting of the piston GI to a position illustrated in dotted lines at GI which is the innermost position required for Diesel operation. At that time the pivots I08, I09 and III move from the positions illustrated in full lines in Figure 8 to the position illustrated in dotted lines. The curve MI is now in the position illustrated in Figure 8. The end of the connecting rod 55 is then swung about its new center 48 of the crank thereby drawing an arc I42. The point of intersection of the arcs MI and I42 represents'the required new pivotal connection between the connecting rod 55 and the walking beam. If the connecting rod is pivoted to the walking beam at this intersecting point, indicated at I 43, the pistons 6| will be in their dotted line position of Figure 8 when the crank 48 is in one extreme position and will be in the full line position of Figure '7 when the crank is in its opposite extreme' position. Thus by shifting the point of pivotal connection of the connecting rod 55 with the walking beam from the point I40 to the point I l-3 the stroke of the piston BIL-6| is increased. All of the increase in stroke takes place during the inward movement of the piston, so that the outermost position of the piston 6| remains the same. The walking beam may be provided with two points for pivotal action with the connecting rod. If it is found that the two required points of pivotal connection are so close together as not to allow room for two separate pins, two

ing beam used for Diesel operation. The pivot points I08; I09 and III are the same relative spacings as in the walking beam illustrated in Figures 7 and 8. The pivot point I43 is located at the intersection of I the curves MI and I42 which is displaced slightly from the center line I45, said center line being the perpendicular bisector of the line I46 joining the centers of the pivots I08I09,

When the engine operates as a Diesel type engine the check valves 24 open directly to the atmosphere. Theopening (Fig. 1) of the engine is provided with a Diesel type fuel injector in lieu of a spark plug such as isused when the engine"operatcs as a gas engine. In operating as aDiesel engine when the pistons are in the position illustrated in Figure l the cylinder 3 has been scavenged of burned gases fromthe pre ceding stroke and is now filled with air at atmospheric pressure. As the pistons approach one another they first close the air intake ports I and then close the exhaust ports 6 and then,

upon continued inward movement of the pistons,

they compress the air within the cylinder. When the pistons reach their innermost limit of motion ach arge of fuel oil is injected into the cylinder by way of the opening 5, as is usual in Diesel type engines. During this inward movement of the piston 6| air has been drawn through the checkvalve 24 into the space in back of the pistons, in the manner previously described. When the fuel is injected into the space between the pistons combustion takes place thus forcing'the pistons apart to make the power stroke of the engine. During their rearward movement the pistons compress the air in back of the pistons, the pistons first uncover the exhaust ports 6 and then the air inlet port I so that the compressed air in the chamber III first sweeps the burned gases from the cylinder 3 and then fills the cylinder with fresh air for the next stroke of the piston.

The engine above described, whether operated as Diesel engine or as an ignition type gas engine, may be ,used for furnishing the power ioroperating a compressor. Figures and 11 illustrate such an engine used to operate four compressor cylinders constituting a two. stage compressor. In Figure 1.0 the engine is of the kind illustrated in Figure 1. The housing IIH has two similar air compressor cylinders I50 and I5I secured thereto in, anydesired manner, as by bolting or the like. The cylinders preferably, although not necessarily, constitute one integral casting and are provided with a cooling water jacket I52. Identical pistons I53 and I54. are located in the cylinders I56 and I5I respectively. The pistons are provided with piston rods'I55 and I56 respectively. The piston rods I55'and I56 are pivotally connected to connecting rods 53' and 55' respectively, which correspond respectively to the connecting rods 53 and 55 of the engine of Figure 1. The connecting rods 53' and 55' are provided with ofisets for furnishing the points of pivotal connection I51 and I58 respectively, with the respective piston rods. The piston rods cannot conveniently be conne cted to the pivot pins I I2 and I I3 respectively, because those pivots are too close together and therefore there is not enough space for the two cylinders I5Il--I5I.

The housing lllil is provided with a set of cylinders I63 and I 64 similar to the cylinders I5il and I 5| ands'imilarly connected to the corresponding connecting rods on the opposite sides of the engine, which connecting rods are of the same shape as the connecting rods 53' and 55. Each of the four cylinders are air compression cylinders and are provided with the usual inlet and outlet air ports I (it and IISE controlled by check or other type of valves, asis well known in the compressor art. In the preferred construction three ofthe cylinders receive air from the atmosphere and deliver it to a single mani fold or tank at a gauge pressure of 30 "pounds per square inch or 45 pounds absolute pressure. The fourth cylinder receives air from that compression tank at the intake side of the cylinder and delivers air to another tank at a pressureof 135 pounds per square inch absolute. The four compressor cylinders I50, I5I, its 3.1161154 thus comprise a two stage compressor designed to deliver air at approximately pounds per square inch gauge pressure. The valves and unloading devices used in connection with the compressor may be ofthe well known types now in common use.

The crank shaft 48 of the engine of Figures 1 and 10 also drives a suitable heavy fly whee1 I?!) for the usual purposes.

In the design shown the engine piston and the compressor pisto-nhave equal strokes. Thisis not an indispensable part of the present invention since any desired ratio of the strokeoi the engine piston with respect to the compressor piston can be obtained either by varying the ratio of the engine piston stroke to the throw of the crank shaft 48 or by connecting the air compressor piston rods I55I56 to the walking beam of the corresponding straight line mechanism NIL-H33.

Inthe engine compressor unit of Figureli) the scavenging air cylinders i35i36 of Figure 6 have been omitted for the sake of.simplification. It is, however, to be understood that those cylinders may be provided in addition to the compressor cylinders illustrated in Figure 10. The scavenging cylinders 55-436 act at such low pressures and do so little work that they do not-cause any appreciable unbalance of the engine or wear on the pivot pins that connect these pistons with the walking beamstructure;

The scavenging air cylinders are provided only when operating the engine as a Diesel engine, not while operating as a gas engine. i i

By making the pistons of the compressor sin-- gle acting they can he splash lubricated by the splash lubricating system of the engine. Because the air compressor pistons are single actingand their piston rods are 'connectedto the linkage in the manner indicated, the thrusts that are set up while compressing the air act upon the pivot pins in the same directions as those that are set up by power pistons of the engine with advantages that have been discussed above in connection with the discussion of the balance in the operation of the engine. I

The only important friction generating surfaces that result from the addition oftheeir compressor cylinders to the engine arethe rubbing surfaces of the air compressor pistonson their cylinder walls. Because the angularities of p the connecting rods that drive the air compressor pistons are small these added frictional losses will also be quite small and the overall mechanical efficiency of the combination engine and air compressor will be higher than that of two independent units coupled together.

The engine of Figure is particularly adapted for furnishing compressed air in apneumatic power system, such as shown in my pendin application entitled, Pneumatic power unit, filed of even date herewith. If the unit of Figure 10 is designed to furnish compressed air to such a system the low pressure air ports 166 are all connected to a common low pressure main and the'outlet or high pressure ports H56" are all connected to a high pressure main-it being under.- stood that each cylinder inlet and outlet is provided with an automatic valve. In the case of the inlet valves the valves are spring seated and arranged to open whenever the pressure in thecylinder falls" below the pressure of the main to which the inlet ports are connected. In the case of the outlet valves the valves are also spring seated and are arranged to open whenever the pressure in the cylinder exceeds the pressure in the main to which the port is connected and to close whenever the pressure in the cylinder is less than the pressure in the main to which the valve is connected. Such valves are well known and may be of the type described and illustrated in Marks Mechanical Engineers Handbook, third edition, page 1866. If it is desired to provide for automatically disabling any selected one or more of the compressor cylinders to reduce the compressed air output'of the unit, the inlet valves may be provided with pneumatically controlled unloading devices of the type known in the art. One suitable type of unloading device is illustrated in Figure l3 of my co-pending applicm tion for Letters Patent covering Pneumatic power unit, filed of even date herewith. This is the type of unloading device described and illustrated in Marks Mechanical Engineers Handbook, third edition, page 1873.

While the four air compressor cylinders of the engine of Figure 10 have all been shown as being of the same diameters, this is not indispensable as they may be of different diameters in order that different outputs may be obtained by using different combinations of compressor cylinders. In compliance with the requirements of the patent statutes I have here shown and described a preferred embodiment of my invention. It is, however, to be understood that the invention is not limited to the precise constructions here shown, the same being merely illustrative of the principles of the invention. What I consider new and desire to secure by Letters Patent is:

1. An engine having two parallel cylinders, opposed pistons in each cylinder, a crank shaft between the two cylinders and rotatable about an axis at right angles to the longitudinal axes of the cylinders, said crank shaft having two crank throws substantially 180 apart, driving connections between one crank throw and diagonally opposite pistons of the two cylinders, driving 1 connections between the other crank throw and the remaining two diagonally opposite pistons, a crank case for the crank shaft, said case being between the cylinders and open at both ends, and housings at the opposite ends of the crank shaft, each housing overlying an end of both cylinders and an open end of the'crank case and supporting at least parts of said driving connections.

2. In an engine having a piston, a piston rod connected at one end to the piston, a straight line motion mechanism including a beam pivoted intermediate its ends about a pair of axes so spaced thata point on thebeam moves in substantially a straight ;line, a pivotal connection between the piston rod and a straight line motion point of the beam, a crank shaft. rotatable about an, axis spaced from and at right angles to the longitudinal'axis of the piston, and a driving connection including a connecting rod between the crank shaft and the beam. 3. A device or the character described comprising a linkage including a pivoted beam having a point thereon adapted tooscillate over a limited distance along a-substantially straight line, a. piston movable in a direction parallel to said line, a

piston rod connecting the piston with the beam at said point on thelinka'ge, a second piston opposite the first piston and movable towards and away therefrom, a piston rod connected to the second piston, a second linkage similar to the first linkage and'similarly connected, to the second piston rod, a crank shaft located centrally between the pistons and at right angles to their line of motion, and separate crank connecting rods connected to the respective beams at points movable in directions substantially opposite to the directions of movement of the respective straight line motion points.

4. In combination with a pair of coaxial oppositely reciprocating pistons, piston rods for the respective pistons, a crank shaft between and at right angles to the pistons, straight line motion mechanisms pivoted about fixed axes adjacent each piston rod-andeach including a beam one point of which is constrained by the mechanism for movement in a straight line, a pivotal connection between said point and the adjacent piston rod, and connecting rods between the crank shaft and the respective beams.

5. In an engine having a pair of opposed pistons and. piston rods, two walking beams one for each piston rod, pivotally mounted means for guiding the movement of each beam so that a point thereof moves in substantially a straight line, a pivotal connection between each piston rod and the'straight line motion point of its associated beam, a crank shaft substantially equidistant from the two pistons and with its axis of rotation at right angles to the directions of travel of the pistons, and connecting rods extending'in opposite directions from the crank shaft to said walking beams.

6. An engine comprising a cylinder open at I both ends, opposed double acting pistons in said cylinder, closures for the opposite ends of the cylinder, piston rods extending from the pistons through the respective end closures, a crank shaft located substantially centrally of the cylinder and with its axis of rotation at right angles to the longitudinal axis of the cylinder, an open ended crank case for the crank shaft, separate housings over each open end of the crank case, said housings extending over the adjacent ends of the cylinder, straight line motion mechanisms within the respective housings, a connection between each piston rod. and. a straight line motion point of the associated mechanism so that the mechanisms guide the piston rods in straight lines, and connecting rods extending from the crank shaft into the respective housings and connected to the respective straight line motion mechanisms.

'7. In an engine having a cylinder, a double acting piston therein, a piston rod connected at one end to the piston, a straight line motion mechanism including a beam a point on which moves in substantially a straight line, a pivotal'connection, between the piston rod anda straight line motion point of the beam, a crank case extendpiston, and a driving connection including a connecting rod between beam.

8. An engine comprising a cylinder open at both ends, a pair of opposed double acting pistons in the crank shaft and the said cylinder, piston'rods for the pistons, a casing at each end of the cylinder, a crank case between the casing and closed by said casings, a

crank in said crank case and extending at right 9. An engine comprising an open ended cylinder and an open ended crank case with the open ends of both facing in the same direction, a housing overthe open ends of the cylinder and the crank -10. In an engine having a pistoma piston rod connected at one end to the piston, a straight line,

motion mechanism including a beam pivoted in termediate its ends about a pairof axes so spaced that a point on the beam moves in substantially a straight line, a pivotal connection between the piston rod and a straight line motion point of the beam, a crank shaft rotatable about an axis spaced from and at right angles to the longitudinal axis of the piston, a driving connection including a connecting rod between the crank shaft and the beam, a cylinder and a piston therein in alignment with the first mentioned piston, and a driving connection between the second mentioned piston and a straight'line motion mechanism.

11. In combination with a pair of coaxial oppositely reciprocating pistons, piston rodsfor the respective pistons, a crank shaft between and at right angles to the pistons, straight line motion mechanisms pivoted about fixed axes adjacent lit case, a piston in the cylinder, a piston rod connected thereto and extending into the housing,

a crank shaft in the crank case, a connecting rod extending therefrom into the housing, a straight line motion mechanism mounted in the housing and connecting the connecting rod with the piston rod, the mechanism having a straight line motion point the locus of which is parallel to the longitudinal axis of the cylinder, and the piston rod being connectedto said mechanism at said straight line motion point thereof.

each piston rod and each including a beam one point of which is constrained by themechanism for movement in a straight line, a pivotal connection between said pointand the adjacent piston rod, connecting rods between the crank shaft and the respective beams, separate cylinders spaced from the pair of oppositely reciprocating pistons, pistons reciprocable in said last mentioned cylinders and driving connections for said last mentioned pistons extending from the respective ones of the last mentioned pistons to the respective straight line motion mechanisms.

ALLEN M. ROSSMAN. 

